Portland Arch Nature Preserve is a nature preserve near the

Wabash River The Wabash River ( French: Ouabache) is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed May 13, 2011 river that drains most of the state of Indiana in the United States. It flows fro ...

in Fountain County, Indiana, USA, and is a National Natural Landmark. The preserve encompasses the wooded valleys, ravines and rocky cliffs around the lowest section of Bear Creek, which flows northwest toward the

. Its name comes from the nearby town of Fountain, which was originally named Portland, and from a natural sandstone bridge carved by a small tributary of Bear Creek. Portland Arch Nature Preserve is managed by the

Indiana Department of Natural Resources The Indiana Department of Natural Resources (DNR) is the agency of the U.S. state of Indiana. There are many divisions within the DNR and each has a specific role. The DNR is not only responsible for maintaining resource areas but also manages In ...

Geology

Portland Arch is one of only a few natural arches in Indiana. The arch was created through the Mansfield Sandstone by Bear Creek, undercutting the bluff on both sides. The sandstone was strong enough that it did not collapse. The Mansfield Sandstone is from the

Pennsylvanian Period The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, in the International Commission on Stratigraphy, ICS geologic timescale, the younger of two period (geology), subperiods (or upper of two system (stratigraphy), s ...

, some 230 million years ago. The cross stratification of the layers were formed in s shallow bottomed lake where it drops into deeper water. The slope reflects the change from the shallows into deeper water. Are like this were used as rock shelters by Native Americans and early pioneers. Along the valley escarpment, talus rocks have fallen into the valley.Portland Arch Nature Preserve and National Natural Landmark; Indiana Department of Natural Resources, Division of Nature Preserves; Indianapolis, Indiana; August 2007

References

External links

Indiana DNR: Portland Arch Nature Preserve

U.S. National Park Service: Portland Arch Nature Preserve
{{authority control Protected areas of Fountain County, Indiana National Natural Landmarks in Indiana Natural arches of Indiana Portland Arch Landforms of Fountain County, Indiana